<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>圆角</title>
    <style type="text/css">
        body{
            background-image: url("../images/big_cola.jpeg");
        }
        .box {
            width: 300px;
            height: 300px;
            border: 3px solid #000;
            background-color: #6DDCBD;
            margin: 100px auto;
            border-top-left-radius: 50%;
            border-top-right-radius: 30%;
            border-bottom-left-radius: 50px 80px;
            border-bottom-right-radius: 60%;
            opacity: 0.3;
            filter: alpha(opacity=30);
        }
        .box2 {
            width: 300px;
            height: 300px;
            border: 3px solid #000;
            background-color: rgba(0,150,0,0.3); /* rgba 设置背景颜色及透明度 */
            margin: 100px auto;
            border-radius: 50%;
            border-bottom-right-radius: 0px;
        }
        .box2:hover{
            opacity: 0.5;
            filter: alpha(opacity=50);/* 透明度 */
        }
    </style>
</head>
<body>
    <div class="box"></div>
    <div class="box2"></div>
</body>
</html>